The Allegretto could not be a greater contrast to the first movement. In E minor, it has a continuous creeping bass-line, rather as in a baroque passacaglia. At first all three instruments state the bass together in octaves. Then the piano continues with the line in the bass, while singing an almost operatic melody above it. But this is no ordinary passacaglia: the bass winds its way, evolving and moving from key to key, until it arrives in G major. Here the stringed instruments join in, and the piano’s melody develops an obsession with a dotted-rhythm figure. This leads to a forceful reprise of the melody with which the piano solo began, but now in the bass, with the passacaglia line above. The movement ends with a series of cadenza-like flourishes. The shape of the whole movement is similar to some of J S Bach’s slow movements—such as those in the Italian Concerto and the violin concertos—but with a new dramatic dimension.
The finale is also full of surprises. The opening theme has quirky phrasing which keeps on subverting the three-in-a-bar metre, and just when you expect the first strain to end after a conventional eight bars, it meanders on for an extra four. In the middle section of the movement, the violin strikes off on its own, in E minor. Then, in a passage which must have seemed outrageous to Haydn’s contemporaries, the music slips sideways into the remote key of E flat minor, before thinking better of it and returning to E minor to finish the section. The quirky opening theme returns at the end, twice interrupted by chromatic moments, as if it wishes to return to the slow movement, before two chords bring the work emphatically to a close.
from notes by Robert Philip © 2009